Rocket Man’s “Performance Issue” Solved.

You may recall a story we did a couple months ago regarding Rocket Mans “Performance Issue” If not we will have a link at the bottom of the story as a reminder. It takes courage to be so open about “Performance Issues” So it’s important that we all support Rocket Man and thank him for the update on his condition.

Sequel to Rocket Man pinging and performance issue

Okay so previously story went something like this – Rocket Man is having a performance issue. Pinging at high RPMs and won’t make it to 3,000 RPMs.
Lots of great opinions from the readers – listed here:
1. Distributor
2. Fuel Mix Too lean
3. Plug wires switched at
4. Go back to points
5. Distributor springs too weak
6. Carbon buildup in engine
7. Dirt in carburetor
8. Timing
9. Higher Octane fuel
10. Worn cam
11. Valve clearances
12. Octane boost
13. Carb jets
14. Wrong valve springs

The most popular response was number 4 – Go back to points. Five responded with that advice.

I also had three well respected people that have helped me along the way, weigh in and there responses were distributor issue, wrong prop and wrong high speed jet in carburetor (fixed in there now versus adjustable).

Now to give a little more background I had gone through everything on this engine and it was either replaced or rebuilt EXCEPT the distributor. Hey, it started, idled smooth and ran good up to 2,000 RPMs. Why worry ?

Well being an engineer and knowing I am supposed to get 3,000 RPMs is a bad combination for settling.

Here is the rest of the story. First action – new larger style distributor and Pertronix from Jim Staib. Jim’s advice was based on the fact that if Chris Craft switched to the larger distributor at some point it was for a good reason.

New larger distributor installed

Well what a difference ! No pinging at all, cleaner exhaust, and 2,700 RPMs all day !

Not quite there yet but a whole lot better. Next was getting 12 x 12 prop from Jim. That was installed and the next run I got my 3,000 RPMs ! Great feeling.

New 12 x 12 prop installed

Blow is ….. a…dash photo proving 3,000 RPMs

Okay so I now have a new appreciation of anyone taking photos at high speed while driving the boat. Right at the instance of taking the photo I got waked by a speed boat and now you can see me generator was charging nicely and my bilge pump was not running. Oh well.

Not to slight any of the opinions given – they were all great suggestions and appreciated.

Now the last dilemma that I need help with. It was Jim Grant on the high speed jet advice and I trust him very much but with what I have going for me now is it worth changing that jet out ?

Mark Bigda –  Rocket Man


12 replies
    • Mike Watson
      Mike Watson says:

      Busy boating before it’s too late in MI. Kids and grand kids up. Wife’s brother and fam for a day. Nine sleeping on the boat. Fishing, pool and boat rides in the SS for all. Mixed in has been bilge diving. No time to read. Off to Saugatuck Thursday for a long ADULT weekend. Glad the problem was solved.

  1. floyd r turbo
    floyd r turbo says:

    I got a 11.5 mile trail run around our local lake, no woodies in sight and mine are far from operable. So Rocket Man’s performance problem is a good one to have. Now that he’s at peak performance everyone’s satisfied. Smoke ’em if ya got ’em.

  2. Rick
    Rick says:

    Spending lots of time on in and around the water. Too sunburned and exhausted to comment much. Frozen margaritas are helping….and making me sleepy.

    • Mark in da U P
      Mark in da U P says:

      Played with my wooden boat today. (If I’d said woody you guys would think I’m perverted) Rocket Man I’m glad you got your problem solved 😅

  3. Jim G
    Jim G says:

    Hi Mark,

    Glad to see you have got it solved. As far as I remember the main (high speed) jet is a 32 or within one size of it. The only way to check is pulling it out and reading the number on it.

    Now that you have the bigger distributor and the fixed jet all you need to do if you want to is add the timing mark to the flywheel. I just picked up these Chris Craft Service Bulletins about 6 months ago. I have been looking for this one for about 20 years. I post the pictures here. Maybe Matt can make it so you can increase the size.

    On the prop you now have the right size. To things that on the prop that can effect your speed. Is there a cup in the blade. If so have it taken out. Also Chris Craft was using the T-36 Federal Mogal design. Which is what the book listing calls for. Other designs can effect your performance one way or the other.

    On the jet. You can take it out and put in the adjustable one I sent you and see if it makes any difference. Just be careful as the leaner you run your engine the faster it will go. But cylinder temps get hotter and can melt pistons.

    The Chris Craft book says you should get 3600 rpm out of the KLC. But there are some factors that can effect this. Besides what is mentioned above. You also have weight factor. A full tank of gas can have some effect also how many people and there weight will also have an effect.

    If you have any other questions you know my number.


    Apparently Matt doesn’t like me anymore as I am blocked from posting pictures.

  4. Troy in ANE
    Troy in ANE says:

    9:42 PM and just checking in.
    Woke up today on Band Aids (On the hook at a BEAUTIFUL anchorage), came home, went for a ride in Gottago, kayaked from boat to boat, and brought On the Fly back into the float.

    Glad Rocket Man is working so well.

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